In an internal combustion engine provided with a variable valve train which can optionally change an opening characteristic of a valve, there has been conventionally executed a control of an ignition timing in correspondence to the opening characteristic of the valve.
As an ignition timing control apparatus executing this kind of ignition timing control, there is a structure which estimates an amount of a burned gas sealed within a cylinder (a combustion chamber), that is, an amount of an internal exhaust gas recirculation on the basis of an overlap period between an intake valve and an exhaust valve, and corrects an ignition timing on the basis of the amount of the internal exhaust gas recirculation (for example, patent document 1).
However, in the ignition timing control apparatus shown in the patent document 1, in the case that a difference is generated between a target valve timing and an actual valve timing at a time of switching a variable valve train or the like, there is executed an ignition timing correction which is different from an actual valve overlap period, so that it is impossible to accurately control the ignition timing.
In this regard, there is an ignition timing control apparatus which detects an actual valve timing and corrects an ignition timing on the basis of a difference between a target valve timing and an actual valve timing (for example, patent document 2).
The ignition timing control apparatus can precisely correct the ignition timing even at a time of switching the variable valve train, however, executes the correction of the ignition timing on the basis of an amount of displacement of the variable valve train timing. Accordingly, the ignition timing control apparatus can not correspond to the ignition timing control of the internal combustion engine having a variable valve train lift mechanism.
Taking this matter into consideration, as a structure for executing an ignition timing correction on the basis of a difference between a target opening timing and an actual opening timing in a transient state of a variable valve train, in an internal combustion engine provided with a variable valve train timing mechanism and a variable valve train lift mechanism, there has been proposed an ignition timing control apparatus structured such as to precisely execute an ignition timing correction even in the transient state of the internal combustion engine provided with the variable valve train timing mechanism and the variable valve train lift mechanism (for example, patent document 3).
Further, there has been proposed an internal combustion engine control apparatus which corrects a detection delay of a load detecting means by using a delay system model of an intake passage from a load detecting means to an intake valve existing in a downstream side of the load detecting means, and computing an amount of a fuel injection on the basis of a corrected amount of a filled air, at a time when an operating characteristic of a variable valve train is changed (for example, patent document 4).
Patent Document 1: JP-A-2001-221105
Patent Document 2: JP-A-9-209895
Patent Document 3: JP-A-2003-201945
Patent Document 4: JP-A-11-264330